ARM: OMAP3: Warn about spurious interrupts
In the case of spurious interrupt, the handler for previous interrupt
handler needs to flush posted writes with a read back of the interrupt
ack register. Warn about handlers that need to flush posted writes.
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/irq.c b/arch/arm/mach-omap2/irq.c
index c40fc37..636e282 100644
--- a/arch/arm/mach-omap2/irq.c
+++ b/arch/arm/mach-omap2/irq.c
@@ -23,6 +23,7 @@
#define INTC_REVISION 0x0000
#define INTC_SYSCONFIG 0x0010
#define INTC_SYSSTATUS 0x0014
+#define INTC_SIR 0x0040
#define INTC_CONTROL 0x0048
#define INTC_MIR_CLEAR0 0x0088
#define INTC_MIR_SET0 0x008c
@@ -60,6 +61,30 @@
return __raw_readl(bank->base_reg + reg);
}
+static int previous_irq;
+
+/*
+ * On 34xx we can get occasional spurious interrupts if the ack from
+ * an interrupt handler does not get posted before we unmask. Warn about
+ * the interrupt handlers that need to flush posted writes.
+ */
+static int omap_check_spurious(unsigned int irq)
+{
+ u32 sir, spurious;
+
+ sir = intc_bank_read_reg(&irq_banks[0], INTC_SIR);
+ spurious = sir >> 6;
+
+ if (spurious > 1) {
+ printk(KERN_WARNING "Spurious irq %i: 0x%08x, please flush "
+ "posted write for irq %i\n",
+ irq, sir, previous_irq);
+ return spurious;
+ }
+
+ return 0;
+}
+
/* XXX: FIQ and additional INTC support (only MPU at the moment) */
static void omap_ack_irq(unsigned int irq)
{
@@ -70,6 +95,20 @@
{
int offset = irq & (~(IRQ_BITS_PER_REG - 1));
+ if (cpu_is_omap34xx()) {
+ int spurious = 0;
+
+ /*
+ * INT_34XX_GPT12_IRQ is also the spurious irq. Maybe because
+ * it is the highest irq number?
+ */
+ if (irq == INT_34XX_GPT12_IRQ)
+ spurious = omap_check_spurious(irq);
+
+ if (!spurious)
+ previous_irq = irq;
+ }
+
irq &= (IRQ_BITS_PER_REG - 1);
intc_bank_write_reg(1 << irq, &irq_banks[0], INTC_MIR_SET0 + offset);
